Synthesizing Indirect Effects in Mediation Models With Meta-Analytic Methods

The mediating effect of institutional trust in the relationship between precarity and conspiracy beliefs: A conceptual replication of Adam-Troian et al. (2023)

The paper reports the results of registered conceptual replications of the indirect effect of institutional trust in the relationship between precarity and the endorsement of conspiracy beliefs (CB). The original study of Adam-Troian et al. (2023; British Journal of Social Psychology, 62(S1), 136-159) indicated that subjective appraisals of economic hardship are associated with lower trust in governments and institutions, which in turn is associated with stronger endorsement of CB. Our Studies 1 to 3 report a series of replications using Slovak panel data. Study 4 reports a replication of the mediation model using data from the European Social Survey Round 10 collected in 17 countries. To provide a quantitative synthesis of these and previous results, we conducted mini meta-analysis (N = 50,340). Although the strength of the observed relationships differed across the studies to some degree, the original patterns of relations remained robust, supporting the original model. The study corroborates the view that to curb the spread of CB, it is necessary to address structural issues, such as growing financial insecurity, socioeconomic inequalities, and the deficit of institutional trust. Finally, we discuss the role of cultural and political settings in conditioning the mechanisms through which precarity enhances the endorsement of CB.

Monte Carlo confidence intervals for the indirect effect with missing data

Missing data is a common occurrence in mediation analysis. As a result, the methods used to construct confidence intervals around the indirect effect should consider missing data. Previous research has demonstrated that, for the indirect effect in data with complete cases, the Monte Carlo method performs as well as nonparametric bootstrap confidence intervals (see MacKinnon et al., Multivariate Behavioral Research, 39(1), 99-128, 2004; Preacher & Selig, Communication Methods and Measures, 6(2), 77-98, 2012; Tofighi & MacKinnon, Structural Equation Modeling: A Multidisciplinary Journal, 23(2), 194-205, 2015). In this manuscript, we propose a simple, fast, and accurate two-step approach for generating confidence intervals for the indirect effect, in the presence of missing data, based on the Monte Carlo method. In the first step, an appropriate method, for example, full-information maximum likelihood or multiple imputation, is used to estimate the parameters and their corresponding sampling variance-covariance matrix in a mediation model. In the second step, the sampling distribution of the indirect effect is simulated using estimates from the first step. A confidence interval is constructed from the resulting sampling distribution. A simulation study with various conditions is presented. Implications of the results for applied research are discussed.

Child maltreatment and resilience in adulthood: a protocol for a systematic review and meta-analysis

Background: Although child maltreatment (CM) has been linked to health problems and poor psychosocial functioning, not all individuals exposed to CM develop or experience negative consequences later in life. This suggests that some individuals show resilience after being exposed to CM. However, conclusions have been limited by inconsistent findings across different CM subtypes and resilience domains.Objective: To develop a protocol for conducting a systematic review and meta-analysis to quantify associations between CM (overall and its subtypes) and resilience (global and its multiple domains) in adulthood, and to examine moderators and mediators of these associations.Method: PubMed, PsycINFO, Embase, Scopus, and Web of Science will be searched to identify relevant studies on the association between CM (exposure) and resilience (outcome) in adults (≥ 18 years). Data will be screened and extracted by at least two independent reviewers. The methodological quality of the included studies will be independently assessed with a modified version of the Newcastle-Ottawa Scale (NOS). If deemed viable, a meta-analysis will be conducted using a random effects model. Heterogeneity of evidence will be estimated with the I2 statistic, and publication bias will be assessed. The effects of potential moderators (e.g. timing and severity of CM, age, sex, family cohesion, socio-economic status, country/region) will be analysed using meta-regression and subgroup analyses, and meta-analytical structural equation modelling will be employed to synthesise indirect mediation effects. Candidate moderators and mediators (e.g. genetic factors, brain functioning, attachment style, personality traits, physical activity, and social support) will be also examined qualitatively.Conclusions: This protocol will facilitate a systematic review and meta-analysis that has the potential to enhance our knowledge about the association between CM exposure in early life and resilience in adulthood. Understanding associations and underlying mechanisms between CM and resilience is potentially important in informing prevention and interventions to sustain health and improve outcomes among adults with a history of CM.PROSPERO registration: CRD42023394120.

Acceptance and Commitment Therapy Processes and Mediation: Challenges and How to Address Them

Acceptance and commitment therapy (ACT) emphasizes a focus on theory-driven processes and mediating variables, a laudable approach. The implementation of this approach would be advanced by addressing five challenges, including (a) distinguishing ACT processes in measurement contexts, (b) developing and rigorously validating measures of ACT processes, (c) the wide use of psychometrically weaker ACT process measures and the more limited use of stronger measures in earlier work, (d) the inconsistency of past evidence that ACT processes are sensitive or specific to ACT or mediate ACT outcomes specifically, and (e) improving statistical power and transparency. Drawing on the existing literature, we characterize and provide evidence for each of these challenges. We then offer detailed recommendations for how to address each challenge in ongoing and future work. Given ACT's core focus on theorized processes, improving the measurement and evaluation of these processes would significantly advance the field's understanding of ACT.

Meta-Analyses of the Relationships between Family Systems Practices, Parents' Psychological Health, and Parenting Quality

(1) Background: Family systems theories include assertations that both personal and environmental factors are determinants of parents' psychological health, well-being, and parenting quality. Applied family systems theories focus on determinants that can be operationalized as intervention practices. The analyses described in this paper focused on the direct and indirect effects of four family systems practices (family needs, resources, supports, and strengths), parents' psychological health (depression, well-being, etc.), and parenting quality (parenting beliefs, involvement, and practices) in families of children with identified disabilities, medical conditions, or at-risk conditions for poor outcomes; (2) Methods: Data from previously completed meta-analyses of the relationships between family systems practices and parents' psychological health outcomes and parenting quality outcomes were reanalyzed. Next, a meta-analysis of the relationships between parents' psychological health and parenting quality was completed to identify which predictors were related to which parenting quality outcomes. Both main effects and mediated effects were examined; (3) Results: The four family systems practices were each related to six different psychological health measures and three parenting quality measures. The six different parental psychological health measures were also related to the three parenting quality measures. The relationships between family systems practices and parenting quality were partially mediated by parents' psychological health; (4) Conclusions: The effects of family systems practices and parents' psychological health on parenting quality were primarily direct and independent. The relationships between family systems practices and parenting quality were partially mediated by parents' psychological health. Future research should focus on the identification of other mediator variables found to be important for explaining the indirect effects of family systems practices measures on parenting beliefs, behavior, and practices.

Myokines as mediators of exercise-induced cognitive changes in older adults: protocol for a comprehensive living systematic review and meta-analysis

Background

The world's population is aging, but life expectancy has risen more than healthy life expectancy (HALE). With respect to brain and cognition, the prevalence of neurodegenerative disorders increases with age, affecting health and quality of life, and imposing significant healthcare costs. Although the effects of physical exercise on cognition in advanced age have been widely explored, in-depth fundamental knowledge of the underlying mechanisms of the exercise-induced cognitive improvements is lacking. Recent research suggests that myokines, factors released into the blood circulation by contracting skeletal muscle, may play a role in mediating the beneficial effect of exercise on cognition. Our goal in this ongoing (living) review is to continuously map the rapidly accumulating knowledge on pathways between acute or chronic exercise-induced myokines and cognitive domains enhanced by exercise.

Method

Randomized controlled studies will be systematically collected at baseline and every 6 months for at least 5 years. Literature search will be performed online in PubMed, EMBASE, PsycINFO, Web of Science, SportDiscus, LILACS, IBECS, CINAHL, SCOPUS, ICTRP, and ClinicalTrials.gov. Risk of bias will be assessed using the Revised Cochrane Risk of Bias tool (ROB 2). A random effects meta-analysis with mediation analysis using meta-analytic structural equation modeling (MASEM) will be performed. The primary research question is to what extent exercise-induced myokines serve as mediators of cognitive function. Secondarily, the pooled effect size of specific exercise characteristics (e.g., mode of exercise) or specific older adults' populations (e.g., cognitively impaired) on the relationship between exercise, myokines, and cognition will be assessed. The review protocol was registered in PROSPERO (CRD42023416996).

Discussion

Understanding the triad relationship between exercise, myokines and cognition will expand the knowledge on multiple integrated network systems communicating between skeletal muscles and other organs such as the brain, thus mediating the beneficial effects of exercise on health and performance. It may also have practical implications, e.g., if a certain myokine is found to be a mediator between exercise and cognition, the optimal exercise characteristics for inducing this myokine can be prescribed. The living review is expected to improve our state of knowledge and refine exercise regimes for enhancing cognitive functioning in diverse older adults' populations.

Registration

Systematic review and meta-analysis protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO) on the 24th of April 2023 (registration number CRD42023416996).

Cultural threat perceptions predict violent extremism via need for cognitive closure

Understanding the psychological processes that drive violent extremism is a pressing global issue. Across six studies, we demonstrate that perceived cultural threats lead to violent extremism because they increase people's need for cognitive closure (NFC). In general population samples (from Denmark, Afghanistan, Pakistan, France, and an international sample) and a sample of former Mujahideen in Afghanistan, single-level and multilevel mediation analyses revealed that NFC mediated the association between perceived cultural threats and violent extremist outcomes. Further, in comparisons between the sample of former Afghan Mujahideen and the general population sample from Afghanistan following the known-group paradigm, the former Mujahideen scored significantly higher on cultural threat, NFC, and violent extremist outcomes. Moreover, the proposed model successfully differentiated former Afghan Mujahideen participants from the general Afghan participants. Next, two preregistered experiments provided causal support for the model. Experimentally manipulating the predictor (cultural threat) in Pakistan led to higher scores on the mediator (NFC) and dependent variables (violent extremist outcomes). Finally, an experiment conducted in France demonstrated the causal effect of the mediator (NFC) on violent extremist outcomes. Two internal meta-analyses using state-of-the-art methods (i.e., meta-analytic structural equation modeling and pooled indirect effects analyses) further demonstrated the robustness of our results across the different extremist outcomes, designs, populations, and settings. Cultural threat perceptions seem to drive violent extremism by eliciting a need for cognitive closure.

Advanced methods and implementations for the meta-analyses of animal models: Current practices and future recommendations

Meta-analytic techniques have been widely used to synthesize data from animal models of human diseases and conditions, but these analyses often face two statistical challenges due to complex nature of animal data (e.g., multiple effect sizes and multiple species): statistical dependency and confounding heterogeneity. These challenges can lead to unreliable and less informative evidence, which hinders the translation of findings from animal to human studies. We present a literature survey of meta-analysis using animal models (animal meta-analysis), showing that these issues are not adequately addressed in current practice. To address these challenges, we propose a meta-analytic framework based on multilevel (linear mixed-effects) models. Through conceptualization, formulations, and worked examples, we illustrate how this framework can appropriately address these issues while allowing for testing new questions. Additionally, we introduce other advanced techniques such as multivariate models, robust variance estimation, and meta-analysis of emergent effect sizes, which can deliver robust inferences and novel biological insights. We also provide a tutorial with annotated R code to demonstrate the implementation of these techniques.

Mediators and moderators in the relationship between maternal childhood adversity and children's emotional and behavioural development: a systematic review and meta-analysis

Maternal experiences of childhood adversity can increase the risk of emotional and behavioural problems in their children. This systematic review and meta-analysis provide the first narrative and quantitative synthesis of the mediators and moderators involved in the link between maternal childhood adversity and children's emotional and behavioural development. We searched EMBASE, PsycINFO, Medline, Cochrane Library, grey literature and reference lists. Studies published up to February 2021 were included if they explored mediators or moderators between maternal childhood adversity and their children's emotional and behavioural development. Data were synthesised narratively and quantitatively by meta-analytic approaches. The search yielded 781 articles, with 74 full-text articles reviewed, and 41 studies meeting inclusion criteria. Maternal mental health was a significant individual-level mediator, while child traumatic experiences and insecure maternal-child attachment were consistent family-level mediators. However, the evidence for community-level mediators was limited. A meta-analysis of nine single-mediating analyses from five studies indicated three mediating pathways: maternal depression, negative parenting practices and maternal insecure attachment, with pooled indirect standardised effects of 0.10 [95% CI (0.03-0.17)), 0.01 (95% CI (-0.02 to 0.04)] and 0.07 [95% CI (0.01-0.12)], respectively. Research studies on moderators were few and identified some individual-level factors, such as child sex (e.g. the mediating role of parenting practices being only significant in girls), biological factors (e.g. maternal cortisol level) and genetic factors (e.g. child's serotonin-transporter genotype). In conclusion, maternal depression and maternal insecure attachment are two established mediating pathways that can explain the link between maternal childhood adversity and their children's emotional and behavioural development and offer opportunities for intervention.

Meta-analyzing intelligence and religiosity associations: Evidence from the multiverse

Over the past century, a remarkable body of research about the relationship of intelligence and religiosity has accumulated. So far, the majority of studies that investigated this relationship showed a negative correlation, indicating lower cognitive abilities of individuals reporting stronger religious beliefs. Although the effect direction has been observed to be largely consistent across studies, the reported effect strength varied substantially across studies. Several potentially moderating variables such as different intelligence and religiosity assessment methods, educational status of samples, and participant sex have been proposed as likely candidates for explaining systematic differences in effect strengths. However, the effects of these moderators are to date unclear. Consequently, we focused in investigating effects of these moderating variables on the intelligence and religiosity link in an update of prior meta-analytical investigations in n = 89 (k = 105; N = 201,457) studies. Random-effects analyses showed a small but robust negative association between intelligence and religiosity r = -.14 (p < .001; 95% CI [-.17, -.12]). Effects were stronger for (i) psychometric intelligence tests than for proxy measures such as grade point averages and (ii) general population and college samples than pre-college samples. Moreover, we provide evidence from combinatorial, multiverse, and specification curve analyses that further corroborates the robustness of the investigated association. Out of 192 reasonable specifications all 135 (70.4%) significant summary effects were negative. In all, our results show small but robust negative associations between religiosity and intelligence that are differentiated in strength but generalize in terms of direction over moderating variables.